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Helping to prevent sewer overflows and backups is easy

Most of the time, the City's sewer pipes have adequate capacity to carry wastewater to the treatment plant. But during heavy, extended raining periods when the ground water is high, the capacity of some sections of the sewer system is exceeded. Ground water or surface water will enter older sewer pipes through cracks and, added to the wastewater flow, will exceed the space available in the pipe. When these conditions occur the water has to go somewhere. If it can't flow down the main pipe, it will back up into the service line and, possibly, all the way into the basement.

The wastewater collection system in Corvallis gathers sanitary sewage from sinks, tubs, toilets, and other household and commercial drains, and transfers it to the wastewater plant for treatment. There are over 200 miles of pipe ranging in size from 4 to 72 inches in diameter that make up the collection system, along with 3,900 manholes which provide access to the system. 

In the older sections of Corvallis (about 30% of the entire collection system), the sanitary and storm systems are combined and go to the wastewater plant for treatment.